Saturday, April 30, 2011

Weekend Bonus: Music and the Brain

This past Tuesday, I attended a symposium on Music and the Brain. The subject is a fascinating one, and it is one that has been mentioned in part in this blog before.

There is a common mis-statement of *lateralization* of brain function. Popular science and psychology magazines promote the concept that analytic functions are confined to the left hemisphere of the brain, and artistic functions (including music) are confined to the right hemisphere. While there is *some* lateralization, the statement is so simplistic as to be false. However, when it comes to speech, there is a clear concentration of neural function in Broca's area to in the left frontal lobe - it is not exclusive, and the right side can take over function in the event of damage. That was one of the main subjects of the symposium - use of music: melody and rhythm to restore speech in patients with stroke or head injury that damages the brain regions involved in speech.

Interestingly, humming and singing does *not* involve the same part of the brain as speech. Patients with "aphasia" are unable to speak some or all words (even though the same patient can read or write those same words) can hum or even sing those same words! By capitalizing on this remaining brain function, Dr. Gottfried Schlaug of Beth Israel Deaconess Medical Center and Harvard University is using melody and rhythm to restore speech in patients with damage to speech centers.

The "arcuate fasciculus," shown above, appears to play a major role in speech, but more importantly in music. The fasciculus is mistakenly cited as connecting Wernicke's with Broca's areas. But as can be seen, it extends much further, connecting most of the Temporal Lobe with the Frontal Lobe - including, but not limited to, the language (Wernicke's) and speech (Broca's) centers.

Next up was a fascinating talk using MRI and PET imaging techniques to look at active regions of the brain during music performance, conducting, listening and even imagining. Dr. Donald Hodges of UNC Greensboro revealed some surprises - for example, a professional musician actually has *lower* activity in the frontal lobe when performing. While the exact reason is not precisely known, the researchers and musicians agree that excessive *thinking* is counterproductive to a trained musician, and the reduce frontal activity could be a means of "getting the brain out of the way."

Other amazing findings come from scans of music conductors - whether playing, conducting or just *imagining* a musical performance, professional musicians activate a *lot* of the brain - motor areas, auditory areas, the "melody circuit" (arcuate fasciculus), visual areas, cerebellum and many other areas involved in processing music. These findings were confirmed by Dr. Jonathan Burdette of Wake Forest Medical School, who described the networks of brain areas involved in music perception and performance. One of the important conclusions is that music is *not* lateralized to just one half of the brain! Nor is the center for processing music confined to just one area. Music activates a wide network of neurons through all of the brain, left, right, front, back, top, bottom - and may turn out to be one of the most fundamental networks of the human cognitive function.

I regret that I could not attend the final talk, in which Dr. Patricia Gray of UNCG spoke of finding brain networks in Great Apes that respond to rhythm and essential elements of music. It is a fascinating study that shows that while melody generation exists in some lower species (i.e. birdsong) - the concept of *music* is a function of the cognitive functioning of the higher primates.

All in all a fascinating series of lectures, and reinforcement that the human brain is a strange and wonderful thing.

So, until next time, take care of your brain - and feed it some music!